-.BI "\-H, \-\-history " file
-Reads a file and displays the contents in a drop-down list, as for
-.B \-\-list
-above. Once the user has entered a string, a new list written to
-.I file
-containing the newly entered string as the first item; other lines
-matching the newly entered string are not written.
+.BI "\-p, \-\-prompt " prompt
+Sets the prompt string in the dialogue box to
+.IR prompt .
+If the prompt string contains an underscore character
+.RB ` _ ',
+then the following character appears underlined; pressing Alt and the
+leftmost underlined character (the `mnemonic') moves the input focus to
+the entry widget. If you want a literal underscore, type two
+consecutive underscores. The default is to have no prompt string.